The science behind the long slow run is that you are supposed to be running it in a heart rate zone that is of benefit to your aerobic system (an easy/converational pace at between 70-80% of max heart rate. Marathon pace....or any race pace would be in an anaerobic heart rate zone (above 80% max heart rate).

Put in layman's terms, a better developed aerobic system is of great benefit to distance runners.

If all training was done at anaerobic pace there would be a greater chance of burnout, injury, lack of improvement. Plus the individual would be missing out on developing a vital component of their running.

JN2 - you wouldn't get very far in a marathon running anaerobically. Marathon pace is an aerobic pace. There are plenty of good reasons to slow the runs down, but it more for saving something for midweek training, getting the body used to efficient fat utilisation, improving glycogen storage etc.

This is not to say that no Marathon Pace should be run on the LR's. Progressive pacing on some runs is useful. Have a look for example on the McMillan site:
http://www.mcmillanrunning.com/articlePages/article/2

they say it takes about 3 weeks to recover from a marathon.........so if you run 18/20 miles at marathon pace then you will take a week or two to recver.........so all the seessions inbetween aren't as good and the next long run is harder ......

and so by the time you get to the start line you are knackered.......

so run slower and get the time on your legs..........If your long runs feel good then personally i think it can be good to put some marathon pace miles at the end of the run.maybe twice a month.......from 5 to 10 miles depending on how you are feeling in the second half of the run.

JN2 - you wouldn't get very far in a marathon running anaerobically. Marathon pace is an aerobic pace. There are plenty of good reasons to slow the runs down, but it more for saving something for midweek training, getting the body used to efficient fat utilisation, improving glycogen storage etc.

This is not to say that no Marathon Pace should be run on the LR's. Progressive pacing on some runs is useful. Have a look for example on the McMillan site: http://www.mcmillanrunning.com/articlePages/article/2

I think you'd find that marathon race pace would be in an anaerobic heart rate zone for those wanting personal bests rather than simply completion.

McMillan themselves predict based on my previous race times that I'd do a marathon in something like 2 hours 49 mins (6:27 per mile) .......and believe me, this pace would certainly take me into an anaerobic heartrate zone within a couple of miles.

JN2, are you sure about that? My understanding is that anaerobic means "without oxygen", i.e. you are running so fast that your respiratory system can't keep up with your oxygen demands.

This is fine for a sprinter, but would theoretically suffocate an endurance runner. I thought this was why the 400m is more than twice as hard as a 200m, as even a highly trained athlete can't maintain anaerobic running for the whole 400m?

JN2 - No idea where you are getting this from. Marathons are about 1% anaerobic, 100m sprint more in the region of 85% anaerobic. Are you sure you are training for the right distance?

Marathon pace is generally at the extreme of your aerobic threshold, so while at the moment I am comfortable running 6:27 min/mile for 20miles, at 6:20 min/miles over 20miles I enter anaerobic territitory and will be crippled with lactic acid unless I back off. Working on increasing anaerobic threshold is therefore key.

JN2, are you sure about that? My understanding is that anaerobic means "without oxygen", i.e. you are running so fast that your respiratory system can't keep up with your oxygen demands.

This is fine for a sprinter, but would theoretically suffocate an endurance runner. I thought this was why the 400m is more than twice as hard as a 200m, as even a highly trained athlete can't maintain anaerobic running for the whole 400m?

JN2 - No idea where you are getting this from. Marathons are about 1% anaerobic, 100m sprint more in the region of 85% anaerobic. Are you sure you are training for the right distance?

Marathon pace is generally at the extreme of your aerobic threshold, so while at the moment I am comfortable running 6:27 min/mile for 20miles, at 6:20 min/miles over 20miles I enter anaerobic territitory and will be crippled with lactic acid unless I back off. Working on increasing anaerobic threshold is therefore key.

Just a thought, but have you ever taken your heart rate when running these 6:27 miles? Obviously I have no idea of your levels of marathon competence but I'd be surprised if you weren't above 80% of MHR after running them constantly for a few miles.

Strangely 6:27 is my predicted marathon pace and I did 10 miles at this exact pace last Saturday.....but I'd bet my heart rate would be in the region of 85-86% of max. Obviously you might well be much fitter.....and 6:27 pace wouldn't take you out of your aerobic zone. You might well be below 80% of max at this pace......but I'd be impressed if that were the case.

JN - If someone is running a marathon at 6,27 - YES their heart rate is below their lactic threshold. That is what the right kind of training does for you - it enables you to run fast at a lower heart rate.

JN - If someone is running a marathon at 6,27 - YES their heart rate is below their lactic threshold. That is what the right kind of training does for you - it enables you to run fast at a lower heart rate.

Agreed.

It doesn't mean that you'd run a marathon with your heartrate below 80% of max though. Some people may well be able to maintain a marathon pace at 85% or higher of the maximum heart rate for the full 26.2 miles. I can't really comment on the correlation/variations between lactic thresholds and an athlete's maximum heart rate. The Fox and Haskell chart is largely generic, but training zones and paces are very much supported by the Daniels VDOT system.....and there does seem to be quite a difference between ones predicted 'easy running pace/long slow run pace' and 'marathon pace'. For me it differs by around one minute per mile, which almost certainly would differentiate an aerobic training zone from an anaerobic training zone.

Granted, everyone is different and no doubt the Fox and Haskell chart that I posted up earlier won't be an exact fit for everyone. But training to training zones based on maximum heart rates is nothing new.

Getting back to the purpose of the thread, the benefit of the long slow run is simply to build up endurance at a slower pace with a lower heart rate so as to be of benefit to a runner's aerobic system and hence be of benefit to their running. The slower pace also is of benefit in so far as a runner is less likely to pick up an injury that they might at a higher pace.

Lactic thresholds are not at 80% -you can estmate them at 85% but even then that is an estimate - the zones always are always unless you get properly tested. I have been and so I know my threshold HR for bike and run but didn't really max out - it did look like my bike threshold is at 83% max and my running threshold is 88% max. So from that you can instantly tell that I have a lot more experience in running. So, if I run a marathon at 85% - this is still aerobic for me - although there will be period where I go over and periods where I dip down. However I suspect this would still be too much for me and I am more likely to race at 80 ish - have never worn a hr strap in a race because of the likelihood of major skin chaffing.

This is why endurance LSR tends to be recommended at 80 - so that you are well below. I believe Maffetone is even lower than that to ensure maximum aerobic training.

So, even though someone is running a marathon at a HR that is edging on 85% (not that I am saying they are - just taking that as an example) - if they can sustain this for a marathon then this must be below their threshold. Therefore calling it anerobic is incorrect. A marathon pace has to be aerobic or it is not sustainable.

So... I ran a half marathon yesterday. I was kept to 8min 20s for 10 miles - this was definitely running, definitely some effort, but I guess I could have kept it going for quite a longer. As it was, I was able to step it up for the last 3 miles. Would it be fair to say that 8:20 represents my LT? Which would presumably mean 9:50 would be a good pace for my long slow runs.

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